Audio ICs 5-channel graphic equalizer - BEN

1 Audio ICs 5-channel graphic equalizer BA3812L. The BA3812L is a five-point graphic equalizer that has all the required functions integrated onto one IC. The IC is com- prised of the five tone control circuits and input and output buffer amplifiers. The BA3812L features low distortion, low noise, and wide dynamic range, and is an ideal choice for Hi-Fi stereo applica- tions. It also has a wide operating voltage range ( to 16V), which means that it can be adapted for use with most types of stereo equipment. The five center frequencies are independently set using external capacitors, and as the output stage buffer amplifier and tone control section are independent circuits, fine control over a part of the frequency bandwidth is possible, By using two BA3812Ls, it is possible to construct a 10-point graphic equalizer .

2 The amount of boost and cut can be set by external components. Applications Radio cassette players, home stereo systems and car stereo systems. Features 1) Minimizes the number of components required to 4) Low current dissipation (5 mA). build a graphic equalizer . 5) Wide dynamic range (VOM = / VCC = 8V). 2) Low distortion and low noise. 6) Built-in input and output buffer amplifiers. 3) Wide operating power supply voltage range ( to 16V). Absolute maximum ratings (Ta = 25 C). Recommended operating conditions (Ta = 25 C).

3 445. Audio ICs BA3812L. Block diagram Electrical characteristics (unless otherwise noted, Ta = 25 C, VCC = 8V, and fin = 1kHz). 446. Audio ICs BA3812L. Measurement circuit Application example 447. Audio ICs BA3812L. By using more than one IC the following applications are (2) 7-point stereo graphic equalizer also possible: As shown in Fig. 3, with three ICs it is possible to (1) 10-point single- channel graphic equalizer construct a 7-point stereo graphic equalizer . Two As shown in Fig. 2, with two ICs it is possible to construct BA3812L ICs are used to construct a 5-point stereo a 10-point single- channel graphic equalizer , graphic equalizer , and two of the active inductor circuits from a third BA3812L are added to each.

4 448. Audio ICs BA3812L. Solid-state inductor The resonance frequency is obtained from the following A solid state inductor uses an active element and has the formula: equivalent function of an inductor. The circuit shown in 1. Fig. 4 is used in the BA3812L. This circuit employs two fo (Hz) = (R: , C: F). capacitors, a potentiometer, and a bias capacitor as ex- 2 R0R1CC0. ternal components, everything else is on the chip. Q is the factor that determines the bandwidth of the fre- The resonance frequency (fo) and the Q of the circuit are quency.

5 If the amount of boost and cut are the same for fixed by the values of the external capacitors. the same resonance frequency, the larger the value of Q, the narrower the resonant frequency band. The circuit Q is obtained from the following formula: Q= CR1. CO RO. Electrical characteristic curves 449. Audio ICs BA3812L. External dimensions (Units: mm). 450.